Invalid chair having footrest braking means



Sept. 30, 1952 L. R. ALLDREDGE ETAL INVALID CHAIR HAVING FOOTRESTBRAKING MEANS Filed July 15, 1948 Sept. 30, 1952 1.. R. ALLDREDGE ETAL2,209

INVALID CHAIR HAVING FOOTREST BRAKING MEANS Filed July 15, 1948 2SHEETS-SHEET 2 Patented Sept. 30, 1952 INVALID CHAIR HAVING FOOTREISTBRAKING MEANS Leroy RrAlldredge', Kensington, and Erick '0. p:Schonstedt, Takoma Park, Md.

Application July 15, 1948, Serial No. 38,776

7 Claims. (01.155-30) 1 v This invention relatesto folding wheel chairs.More particularly, this invention relates to folding wheel chairs of thetype or character intended for use by invalids o'f any age inhomes,hospitals, and like places; as well as for useoutside upon sidewalks andother relatively flat, hard surfaces. r

An object of the invention is to provide anew and improved folding-typeinvalid chair ofeX- "tremely simple and economical constructionemploying essentially only two rigid wheel-bearing frame pieces with asingle pivotal connection between them arranged in such a manner so thatwith very little eifo-rt the chair may be changed from a stable useableposition to a folded .position for ease of transport and storage.

A further object of this invention is to provide an invalid chair. withload concentrating members arranged in such a way as to reduce to a lowvalue the force transmitted through the pivotal means about which thechair folds when an invalidis seated in the chair thus permittingconstruction using light weightmaterials With-' out sacrificing strengthand long life.

Another object of this 'inve'ntion-is-to provide a footbcard for aninvalid chair which can be depressed into braking contact with the floorby the application of force thereupon incident to the natural entranceor egress from the chair but Which cannot be depressed accidentally intobraking contact with the floor by the invalid after he is seated in thechair, said footboard being constructed without employing calibratedsprings as are used in certain -prior art folding wheel chairs. r

Additional and further objects; features and advantages of the presentinvention will become apparentfrom: the following description of aninvalid chairaccording toa preferred embodiment of the invention,reference being made to the accompanyingdrawings in which:

Figure 1 is a side elevation view of a wheel chair embodying the novelfeatures of the invention;"

Figure 2 is a front elevation view of the chair shown in Figure 1;.

Figure 3 is a sectional vieW- of the wheel chair as viewed along theline 3-3 in Figure 1 Figure 4 is a sectional view of the wheel chairtaken along the line 4-4 of Figure 2 showing more clearly the footrestlinkage and the support for the forward portion of the seat;

Figure 5 is a view similar to that of Figure 4 and showing the footrestassembly pi'votedinto contact with the supporting surface on which thewheel chair rests;

wheel Figure 6 is a 'side'elevatio'n view of chair in its foldedposition;

Figure -7 is a diagrammatic view of the wheel chair illustrating thedistribution of forces "resulting from a load applied to the seat of thechair whereby the force transmitted pivotal means is kept very low.Referring'now to the diagrams, wherein like reference characters referto like parts throughout the several views, it will be seen that theillustrated embodiment of the invention has a framework consisting oftwo pieces of. formed tubing designated as A and B which are secured inpivotal relation to each other. j

Tube A consists of two substantially symmetrical portions forming sidesof thechair and a horizontal portion llconnecting the side of the chairand forming the top of the chair} Because of the symmetry of the twosides of the Wheel chair, for the sake of simplicity, only one side willbe described. I

From the top of the chair, tube A has a downwardly and slightlyforwardly extending upright section l2 to which backrest I3 is bolted orotherwise secured. Armrest support bracket 14 is pivotally secured tothe upright section, securing means not shown.Thesubstantiallyhorizontal section I5 extends forwardly from uprightsection I2 and supports frame pivot rod 16 passing through an aperturein the said horizontalportion. The frame pivot rod prevented fromleaving the aperture by enlarging its ends or by some other suitablemeans. The substantially vertical section I! supports wheelbearing axlel3 which 'is Welded to said vertical section or otherwise suitablysecured thereto. -Near the lower extremity of said vertical section,footre st pivot'rod I9 is secured to said section. Footboard 2! is'pivotally secured to said fo'otrest pivot, rod such that said footboardbears pivotal relation with said rod. Said rod passes'through an aperture in the bracket 23 as clearly shown in Figure 4.

Tube B has a seat support section24 to which seat 25 is bolted orotherwise suitably secured. Said seat support section is pivotallysecured to frame pivot rod is passing through aperture in' said section.Leg 26 integrally connected to the seat support section has aswivel-type caster 2.1 secured to its end. I

As may be seen from the dashed lines in Figure 3, the seat 25 has aportion in the vicinity of pivot rod l6 which is narrowed to allowpivotal relation between tubes A and .B for folding pur poses withoutinterference between said seat. and tube-A in the vicinity of said pivotrod. Theforthe wheel through the ward portion of the seat is broadenedto a width that is substantially the same as the lateral distancebetween the outside surfaces of the two sides of tube A. Angle 29suitably secured to the underside of said seat bears up againsthorizontal section [5 of tube A to limit the pivot action of tube Brelative to tube A in the counterclockwise direction as viewed in Figure4. The angle is located so as to bear up against tube A at a pointsubstantially near to a vertical plane passing through axle I8 in orderto keep to a low value the load exerted on the frame pivot rod when thewheel chair is occupied.

This feature is best illustrated by referring to Figure 7. The weight ofthe invalid represented by W is applied to the seat which is on frame B.Part of this weight F2 is transmitted directly through the rigid frame Bandthe rear wheel to the floor or supporting surface at the point 1. Theremainder of the weight F1 is transmitted through the angle a to theframe A at the point b. If the point b is designed to be directly overthe front wheel axle c, the portion of the invalids weight which istransmitted to frame A at the point b is subsequently transmittedthrough the front wheel to the floor at e. With this design, the mainfolding pivot axis at d is required to transmit only a small forcesufficient to hold up the weight of the back portion of frame A. In apractical design, in order to preserve the aesthetic appearance of thewheel chair, the point b may be slightly nearer to the pivot axis (1than is shown in Figure '7 without appreciably sacrificing the advantagedescribed above. This design permits the use of light weight metals suchas aluminum havin low bearing strengths relative to steel withoutresorting to expensive means for reducing bearing stresses in the frameat the pivot point.

Referring again to Figures 1 to 6, angle 29 secured to the underside ofthe seat is pivotally connected to arm rest support 3| which in turn ispivotally secured to arm rest bracket l4. Arm rest 32 is screwed orotherwise rigidly secured to said arm rest bracket.

The push rod 33 shown in Figure l is secured to the wheel chair by adetachable means not shown. The push rod is provided with small wheelchairs so that wheel chairs may be propelled by an attendant and hencemay be used as perambulators.

The bumper 34 composed of rubber or some other suitable material havinga high coefficient of rubbing friction with wood or stone is secured tothe forward portion of the underside of the footboard. The rear portionof the footboard is pivotally secured to rod l9 as described previously.A flexible but essentially non-extensible means 35 made of wire rope,chain, or other strong flexible material is securely fastened to thefootboard near its forward end. From the footboard, said flexible meanextends upward and rearwardly and passes over axle l8 upon which itbears and thence rearwardly and slightly downwardly to eyelet 36 on leg26 to which said flexible means is terminated and secured. Any suitablemeans such as a turnbuckle 31 may be used to adjust the length of thisflexible means. Such an adjustment will determine the angle of thefootboard when it is in its operating position.

The operation of the footboard is as follows: When an invalid steps onthe footboard to enter the chair, a tension is produced in the flexiblemeans. This tension causes frame A and frame 13 to rotate slightlyrelative to each other. In

so doing, the distance between the eyelet 36 and the axle I8 shortensand a portion of the flexible means i drawn over the axle enabling thefootboard to pivot such that the bumpers make contact with the floor orground on which the chair rests, thus preventing the chair from runningor tipping. The slight amount by which frame A pivots with respect toframe B causes the front end of the seat to rise by a slight but notobjectional amount.

The location of the footrest pivot rod I9 substantially' directly abovepoint 38 at. which the wheel 39 makes contact with the supportingsurface 4| eliminates any moment arm by which the depression of thefootboard could cause the wheel chair to tip. The frictional contact ofbumpers 34 with said supporting surface prevents the wheel chair fromrunning.

When the invalid transfers the greater part of his weight from thefootboard to the seat, tube B and tube A pivot in the reverse directionincreasing the distance between the eyelet and the axle causing theflexible means to draw the forward portion of the footboard upward sothat the bumpers no longer make contact with the floor. So long as theinvalid remains seated, the invalid cannot pivot the footboard so thatthe bumpers contact the floor. In leaving the chair, the transfer of theinvalids weight from the seat to the footboard depresses the footboardin the manner previously described.

In connection with the description of the folding feature of the wheelchair, refer to Figure 6. As described previously, frame B is pivotallyconnected to frame pivot rod l6 which in turn is secured to frame A. Theaxis about which this pivot action takes place appears as a point inFigure 6 and hence is referred to as point 42. Similarly the axes aboutwhich armrest bracket l4 and armrest support 3| pivot appear as pointsin Figure 6 and they are indicated by 43, 44 and 45. Pivot axes 42, 43,44 and 45 are so located that the links between them form a figure whichis approximately a parallelogram. Therefore, the pivotin of frame A withrespect to frame B is not restrained by the armrest linkage. As viewedin Figure 6, frame B may pivot with respect to frame A in a clockwisedirection until caster 21 touches the footboard. The maximum depth ofthe chair when folded is determined by the size of wheel 39.

To restrain the amount of pivotal motion of the footrest in thecounterclockwise direction as viewed in Figure 6 when the wheel chair isfolded, bracket 23secured to the footboard 2| bears up against thevertical section I! of frame A when the chair is lifted from the floor.

In wheel chairs designed for self-propulsion by invalid children, thesize of the Wheels will be small so that the chair can be easily placedin the trunk or rear passenger compartment of an automobile fortransportation purposes.

The folding linkages and weight distribution of the chair can bedesigned so that the resultant torque exerted by gravity on frame Babout the frame pivot axis will cause frame B to rotate into the foldedposition as shown in Figure 6 when the wheel chair is grasped by the topof the chair and lifted from the floor. When the folded chair is placedon the floor with the large wheels touching and then tilted backslightly, the chair will unfold under its own weight to a stablecondition shown in Figure 4. The ease of folding is particularly usefulsince it permits a person to lift an invalid child from the chair,

hold the child in one arm, lift the chair from the ground with theother, and have the Wheel chair fold in so doing. Conversely, the childcan still be held with one arm as the chair is placed down on the floorwith the other and have the chair unfold automatically to a stableoperating position.

It is realized by the inventors that many variations of the inventionmay be made by those skilled in the art. It is, therefore, not thedesire of the inventors to limit their invention to the form describedherein but only by the spirit and scope of the appended claims.

We claim:

1. A wheel chair of the character disclosed comprising, in combination,a pair of wheel supported frames joined together pivotally about an axisdisposed intermediate the wheel axes of the frames whereby the wheelsupported ends of the frames may be pivoted toward each other, one ofsaid frames having portions depended from the Wheel axis thereof, afootboard pivotally secured to said depended frame portions and extendedtherefrom in a direction away from the wheel axis of the other frame,and means interconnecting the extended portion of said footboard and thewheel supported ends of said other frame for drawing the wheel supportedends of the frames toward each other in response to downward pivotalmovement of the footboard whereby the footboard is lowered pivotally tothe floor into braking engagement therewith.

2. A wheel chair as claimed in claim 1 further characterized by theprovision of an axle disposed at said wheel axis of said one of theframes and said interconnecting means comprises a cable which passesover said axle.

3. In a wheel chair having first and second pivotally connected frameshaving limited pivotal movement with respect to each other sufficient toform a stable chair, the combination of a footboard pivotally connectedalong the rear portion thereof to the first of said frames, a cableconnected to said footboard forward of said pivoted connections thereofwith said first of the frame members and connected to the second of saidframe members, means secured to said first of the frame members abovethe level of said footboard pivotal connection for guiding the cable,means for varying the length of the cable, and bumpers connected to theforward underside of the footboard.

4. In a wheel chair having a pair of pivotally connected wheel supportedframes constructed and arranged for suficient limited pivotal movementwith respect to each other to form a stable chair, the combination of afootboard pivotally connected along the rear edge thereof to one of saidframes and flexible non-extensible means interconnecting the forwardedge of said footboard and the other one of said frames and extendedabove the pivotal connection of the footboard whereby a downward forceon the footboard sufficient to cause pivotal movement of said framemembers causes the footboard to be lowered pivtremities respectively, abackrest secured to said.

depended leg portions, a horizontally disposed U- shaped member havingthe legs thereof disposed parallel with and inwardly of said horizontalleg extensions, a pivotal connection between said horizontal legextensions and said legs of the horizontally disposed U-shaped member,the legs of said horizontally disposed U-shaped member having dependingextensions, casters secured to the lower extremities of said dependingextensions respectively, a seat secured to the legs of said horizontallydisposed U-shaped member, the portion of said seat in the vicinity ofsaid pivotal connection being constructed sufficiently narrow to beinwardly disposed of said horizontal leg ex tensions, said seat beingbroadened in the vicin ity of the bight portion Of said horizontallydisposed U-shaped member so as to bear against said horizontalextensions when the wheel chair is unfolded, a footboard pivotallyconnected to said downwardly extended extremities, and a cable connectedto said footboard at the forward end thereof, said cable extending abovesaid foot* board pivotal connection to at least one of said dependedextensions and secured thereto, where by a downwardforce on saidfootboard sufficient to cause pivotal movement of said U-shaped framemembers causes the footboard to be lowered pivotally into brakingengagement with the floor.

6. A wheel chair as claimed in claim 5 further characterized by theaddition of an axle for said wheels, said cable passing over and bearingagainst said axle.

'7. A wheel chair as claimed in claim 5 further characterized by theaddition of arm rests pivotally connected to said substantially verticalleg portions respectively and extending above and substantially parallelto said horizontal leg extensions, and a pair of brace members pivotallyinterconnecting the forward ends of said arm rests and the forwardportions of said seat respectively whereby the arm rests imposenegligible restraining forces during the folding operation of the chair.

LEROY R. ALLDREDGE. ERICK O. SCHONSTEDT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Bushnell Aug. 21, 1945

